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956 Systemic Lupus Erythematosus

• Signs may wax and wane, confusing response ○ False-positive results can occur with Behavior/Exercise
to treatment. various medications (nonsteroidal antiin- Avoid outdoor activity and/or use topical
VetBooks.ir festation (e.g., abdominal distention due to others) or infections (e.g., heartworm, mucocutaneous lesions.
flammatory drugs [NSAIDs], antibiotics,
• Other complaints relate to specific mani-
sunscreen for patients showing cutaneous or
ehrlichiosis).
nephrotic syndrome)
PHYSICAL EXAM FINDINGS ○ False-positive or false-negative results can Drug Interactions
• Concurrent NSAID and glucocorticoid
occur as a result of different laboratory
Depends on manifestations, which may include standardization, varied quality control administration should be avoided because
• Lameness with swollen, painful joints; the protocols, and other factors. of the potential for GI ulceration.
carpi, tarsi, elbows, and stifles are most • Lupus erythematosus (LE) cell test is rarely • Mycophenolate mofetil may cause diarrhea.
frequently involved. useful (p. 1361)
• Intermittent fever • Thoracic radiographs may reveal pleural or Possible Complications
• Lymphadenopathy and/or splenomegaly pericardial effusion (usually subtle). • Progressive kidney disease
• Cutaneous lesions: erythema, scaling, crust- • Abdominal ultrasonography: usually normal • Infections (e.g., urinary tract infection) from
ing, depigmentation, and alopecia. Lesions • Tick-borne disease titers to rule out diseases long-term immunosuppression
may develop on the skin, mucocutaneous that can mimic SLE (e.g., glomerulonephri-
junctions, and oral cavity. tis, polyarthritis, hematologic changes) Recommended Monitoring
• Cats: feline leukemia virus (FeLV) and • If prednisone is administered, monitor body
Etiology and Pathophysiology feline immunodeficiency virus (FIV) weight and avoid obesity.
• SLE occurs when a stimulus triggers the serologic tests • If immunosuppressive medications are needed
appropriate susceptibility genes in a patient. chronically, a urine culture is indicated q 3
• Triggering factors can include vaccination, Advanced or Confirmatory Testing months even in the absence of clinical signs
drug administration, stress, infection, or • See Disease Forms/Subtypes above of infection.
exposure to UV radiation. • Coombs’ test: indicated if anemia present • Monitor CBC, serum biochemistry profile,
• Antibodies are directed against a broad range but often negative and urinalysis q 3 months after in remission
of nuclear, cytoplasmic, and cell membrane • Platelet autoantibodies: rarely useful • Serum ANA may be useful to detect relapse.
molecules. Antibodies against the patient’s • Rheumatoid factor: usually negative
own DNA are detected with the ANA test. • Immunohistologic evaluation of skin biopsies PROGNOSIS & OUTCOME
(immunoperoxidase and immunofluorescent
DIAGNOSIS staining) may demonstrate immunoglobulin • Not well-known; many cases wax and wane
and complement deposits at the epidermal • Good for most cases
Diagnostic Overview basement membrane, which are specific for • Progressive renal disease indicates guarded
The diagnosis of SLE is not based on a single immune-mediated dermatopathies. prognosis.
test but on the constellation of clinical signs (see
Disease Forms/Subtypes above) and exclusion TREATMENT PEARLS & CONSIDERATIONS
of other possible causes.
Treatment Overview Comments
Differential Diagnosis At least three aspects of treatment should be • The diagnosis of SLE is not based on a single
• Tick-borne disease considered: test but on the constellation of clinical signs
• Neoplasia and paraneoplastic syndromes • Resolve clinical signs and exclusion of other possible causes.
• Bacterial, fungal, or viral infection • Prevent kidney injury • Treatment with doxycycline is useful to
• Other immune-mediated diseases • Because of the natural waxing and waning exclude infectious causes of polyarthropathy.
of the disease, aggressive therapy may not • Perform arthrocentesis on at least three joints,
Initial Database be indicated for all cases. even if not swollen or painful.
• CBC, including manual differential: may • Biopsy of skin lesions must include intact
show anemia, leukocytosis, or leukopenia; Acute General Treatment epithelium. Ulcerated lesions are inherently
platelet count may be normal or low • Prednisone/prednisolone 1 mg/kg PO q nondiagnostic. Erythematous areas adjacent
• Serum biochemical profile: abnormalities 12-24h initially to ulcers yield the most conclusive results.
reflect the site of inflammation (e.g., azotemia • With severe disease, the addition of adjunctive • Many animals are euthanized not because
and hypoalbuminemia with glomerular immunosuppressants (e.g., mycophenolate of progressive disease but due to adverse
involvement) mofetil 10 mg/kg PO q 12h) should be effects of glucocorticoids. Avoid obesity,
• Urinalysis: ± proteinuria; if present, perform considered (p. 60). and routinely monitor for infection of the
urine protein/creatinine ratio, urine culture • Proteinuria may be lessened with enalapril skin and urinary tract.
and susceptibility (C&S) testing 0.5 mg/kg PO q 12h along with dietary • Combination immunosuppressive therapy
• Skin biopsies may reveal inflammatory infil- protein optimization/restriction; may add with mycophenolate mofetil is often more
trates at the dermoepidermal junction and omega-3 fatty acid supplementation (p. 390) effective and has fewer adverse effects than
vacuolar change in the basal columnar cells. prednisone/prednisolone alone.
• Radiographs of affected joints may reveal Chronic Treatment
nonerosive joint swelling. • After all clinical and laboratory abnormalities Prevention
• Arthrocentesis of multiple joints (p. 1059) have resolved, attempt to taper drugs. In Although a link has not been proved, vaccina-
may reveal sterile neutrophilic inflammation. general, decrease doses by one-half every tions should be limited to those considered
• Serum ANA titer (p. 1308) 2-4 weeks while monitoring clinical and essential after the diagnosis of SLE.
○ Serum ANA commonly stated as a laboratory abnormalities.
requirement for the diagnosis of SLE, • The minimal duration of immunosuppressive Technician Tips
but sensitivity and specificity of this test therapy should be 4-6 months. Many of the effects of SLE, notably polyarthri-
are not known for the dog and cat. • If signs recur during drug taper, increase tis, may be painful. Patients showing clinical
○ Normal ranges are determined by indi- level to the previous dose, and attempt to signs that are known or suspected to be caused
vidual laboratories. taper more slowly. by SLE should be handled and walked as gently

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